1. Field of the Invention
This invention is related to the field of integrated circuits, and more particularly to integrated circuits with on-chip memories.
2. Description of the Related Art
Various types of integrated circuits include on-chip memories. For example, integrated circuits can include caches. Integrated circuits that include processors often include caches to provide low latency access to a subset of the data that is also stored in off-chip memories. Generally, caches are hardware-managed memories that store the most recently used data, and the cache management hardware writes copies of data accessed by the processors (or other memory-reading devices in the integrated circuit) to the cache. Data that has been modified can be replaced in the cache by newer data, and the cache management hardware can write the modified data back to the main memory. In some cases, the processors can include prefetch instructions and other cache hints to influence the operation of the cache management hardware and can mark memory non-cacheable to prevent caching, but generally software cannot control the cache management hardware.
Another type of on-chip memory is embedded memory or “local memory”. Such memory is under software control (i.e. software reads and writes the memory and thus directly controls which data is stored in the embedded memory). The embedded memory can have lower latency that external memory, and if the data stored in the embedded memory is accessed frequently, power savings can be achieved as compared to accessing external memory.